Ignore buggy clippy::missing_panics_doc lint

```
error: docs for function which may panic missing `# Panics` section
   --> src/resolve.rs:98:5
    |
98  |     pub fn into_context(mut self) -> ResolveContext {
    |     ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    |
note: first possible panic found here
   --> src/resolve.rs:102:19
    |
102 |         let env = self.env.unwrap();
    |                   ^^^^^^^^^^^^^^^^^
    = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#missing_panics_doc
    = note: `-D clippy::missing-panics-doc` implied by `-D warnings`
    = help: to override `-D warnings` add `#[allow(clippy::missing_panics_doc)]`
```

src/resolve.rs

@@ -94,6 +94,7 @@ impl ResolveOptions {
         self
     }
 
+    #[allow(clippy::missing_panics_doc)] // false positive: this function is #[doc(hidden)]
     #[doc(hidden)] // Not public API.
     pub fn into_context(mut self) -> ResolveContext {
         if self.env.is_none() {